Systems and methods for providing a catheter assembly

ABSTRACT

A system for controlling fluid flow in a catheter assembly is disclosed herein. An intravenous catheter assembly has a catheter adapter and a needle hub, and the catheter adapter has an inner lumen. A septum is disposed within a portion of the inner lumen, and a slit is formed through the septum. A Parylene coating is disposed within the slit of the septum, the Parylene coating has a thickness of between approximately 0.00005 to 0.0005 millimeters. An introducer needle has a first end coupled to the needle hub and the second end extending through the inner lumen of the catheter adapter. A middle portion of the introducer needle is positioned within a portion of the septum.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/703,336, filed Feb. 10, 2010, entitled SYSTEMS AND METHODSFOR PROVIDING A FLUSHABLE CATHETER ASSEMBLY, which claims the benefit ofU.S. Provisional Application No. 61/151,775, filed Feb. 11, 2009,entitled CATHETER VALVE ASSEMBLY, and which is also acontinuation-in-part of U.S. patent application Ser. No. 12/544,625“SYSTEMS AND METHODS FOR PROVIDING A FLUSHABLE CATHETER ASSEMBLY,” filedAug. 20, 2009. This application claims the benefit of and incorporatesby reference each of the above-referenced applications.

BACKGROUND

The current invention relates to infusion devices, specifically toperipheral intravenous (IV) catheters. In particular, the inventionrelates to a flushable peripheral IV catheter assembly having featuresto enable selective activation of fluid flow through the catheterassembly.

Catheters are commonly used for a variety of infusion therapies. Forexample, catheters are used for infusing fluids, such as normal salinesolution, various medicaments, and total parenteral nutrition into apatient, withdrawing blood from a patient, as well as monitoring variousparameters of the patient's vascular system.

Catheters or needles are typically coupled to a catheter adapter toenable attachment of IV tubing to the catheter. Thus, followingplacement of the catheter or needle into the vasculature of a patient,the catheter adapter is coupled to a fluid source via a section of IVtubing. In order to verify proper placement of the needle and/orcatheter in the blood vessel, the clinician generally confirms thatthere is “flashback” of blood in a flashback chamber of the catheterassembly.

Once proper placement of the catheter is confirmed, the clinician mustthen attach the catheter adapter to a section of IV tubing. This processrequires the clinician to manually occlude the vein to preventundesirable exposure to blood. Manual occlusion of the patient veinrequires the clinician to awkwardly maintain pressure on the vein of thepatient while simultaneously coupling the catheter adapter and the IVtubing.

A common, yet undesirable practice is to permit blood to temporarily andfreely flow from the catheter adapter while the clinician locates andcouples the IV tubing to the catheter adapter. Another common practiceis to attach the catheter adapter to the IV tubing prior to placing theneedle or catheter into the vein of the patient. While this method mayprevent undesirable exposure to blood, positive pressure within the IVline may also prevent desirable flashback.

Complications associated with infusion therapy include significantmorbidity and even mortality. Such complications may be caused byregions of stagnant fluid flow within the vascular access device ornearby areas of the extravascular system. These are regions in which theflow of fluid is limited or non-existent due to the conformation of theseptum or valve mechanism in the extravascular system or the fluiddynamics within that area of the extravascular system. Blood, airbubbles or infused medications may become trapped within these regionsof stagnant flow as a result of the limited or non-existent fluid flow.When blood is trapped within the extravascular system bacteria can breedwhich can lead to infections. When a different medication is infusedinto the extravascular system, or the extravascular system is exposed tophysical trauma, the extravascular system's fluid flow may becomealtered, releasing trapped air bubbles or residual medications back intothe active fluid path of the extravascular system. This release of airbubbles and residual medication into the active fluid path extravascularsystem may result in significant complications.

Released air bubbles may block fluid flow through the extravascularsystem and prevent its proper functioning. More seriously, released airbubbles may enter the vascular system of the patient and block bloodflow, causing tissue damage and even stroke. In addition, residualmedications may interact with presently infused medications to causeprecipitates within the extravascular system and prevent its properfunctioning. Furthermore, residual medications may enter the vascularsystem of the patient and cause unintended and/or undesired effects.

Accordingly, there is a need in the art for a catheter assembly thatpermits controlled, desirable flashback without the risk of encounteringundesirable exposure to blood. Furthermore, there is a need in the artto provide a valve mechanism in a catheter assembly that eliminates,prevents, or limits regions of stagnant flow within vascular accessdevices and extravascular system to provide better flush properties.Such a catheter assembly is disclosed herein.

SUMMARY

In order to overcome the limitations discussed above, the presentinvention relates to a flushable peripheral IV catheter assembly havingfeatures to enable selective activation of fluid flow through thecatheter assembly. The catheter assembly of the present inventiongenerally includes a catheter coupled to a catheter adapter. Thecatheter generally includes a metallic material, such as titanium,surgical steel or an alloy as is commonly known in the art. In someembodiments, a polymeric catheter may be used in combination with ametallic introducer needle, as is commonly known and used in the art.

In some embodiments of the present invention, a septum is positionedwithin a lumen of the catheter assembly to prevent or limit flow of afluid through the catheter adapter. The septum generally includes aflexible or semi-flexible material that is compatible with exposure toblood, medicaments, and other fluids commonly encountered duringinfusion procedures. In some embodiments, a groove is provided on aninner surface of the catheter adapter, wherein the septum is seatedwithin the groove. As such, the position of the septum within thecatheter adapter is maintained.

In some implementations of the present invention, a closed or partiallyclosed pathway, such as a slit or small hole is further provided in abarrier surface of the septum. The pathway permits fluid to bypass theseptum and flow though the catheter adapter. In some embodiments, thepathway is a slit that is closed prior to being opened or activated by aprobe or septum activator positioned within the lumen of the catheteradapter. Prior to being opened or activated, the slit prevents passageof fluid through the catheter adapter. Thus, in some embodiments aplurality of air vent channels are interposed between the septum and thegroove to permit air flow through the catheter adapter prior to the slitbeing opened. The air vents prevent buildup of positive pressure withinthe catheter adapter thereby permitting flashback of blood into thecatheter and a forward chamber of the catheter adapter.

The septum activator generally includes a plastic or metallic tubularbody having a probing end and a contact end. The probing end ispositioned adjacent to the pathway of the septum, and the contact end ispositioned adjacent to a proximal opening of the catheter adapter. Theprobing end of the septum activator is advanced through the pathway ofthe septum when a probe is inserted into the proximal opening of thecatheter adapter. As the probe contacts the contact surface of theseptum activator, the septum activator is advanced in a distal directionthrough the catheter adapter whereupon the probing end of the septumactivator opens the pathway through the septum. Once opened, free flowof fluid is enabled through the catheter assembly.

In some aspects, a Parylene coating is disposed on the surface of theseptum, include within the surfaces of the slit of the septum. Thethickness of the coating is between 0.00005 to 0.0005 millimeters inorder to enable the septum to properly open and close. In otherembodiments, the thickness of the coating is between 0.0001 to 0.0002millimeters. The septum can comprise a silicone rubber material and havea tri-slit configuration (three slits meeting at a center point, to forma single opening.)

Finally, the presence of the septum activator within the lumen of thecatheter adapter may result in aberrant fluid flow leading toundesirable stagnation and coagulation of fluids within the catheterassembly. Thus, in some embodiments of the present invention the septumactivator further includes various flow deflectors and/or flow diversionchannels to maintain proper fluid flow within the catheter adapter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In order that the manner in which the above-recited and other featuresand advantages of the invention are obtained will be readily understood,a more particular description of the invention briefly described abovewill be rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. These drawings depict only typicalembodiments of the invention and are not therefore to be considered tolimit the scope of the invention.

FIG. 1 is a cross-sectioned view of an indwelling catheter having aPRIOR ART flow control valve mechanism.

FIG. 2 is a cross-sectioned view of the PRIOR ART indwelling catheter ofFIG. 1 following removal an introducer needle.

FIG. 3 is a cross-sectioned view of the PRIOR ART indwelling catheter ofFIGS. 1 and 2 following insertion of a connector from a vascular accessdevice.

FIG. 4 is a perspective view of an embodiment of a catheter assembly inaccordance with the present invention.

FIG. 5A is an exploded cross-sectioned view of a catheter assembly inaccordance with the present invention.

FIG. 5B is a perspective view of an embodiment of a septum in accordancewith the present invention.

FIG. 6A is a cross-sectioned view of an interior lumen of a catheteradapter demonstrating fluid flow without the presence of a septumactivator in accordance with a representative embodiment of the presentinvention.

FIG. 6B is a perspective view of an embodiment of a septum activator inaccordance with the present invention.

FIG. 6C is a side view of an embodiment of a septum activator disposedin an inner lumen of a catheter adapter in accordance with the presentinvention, following activation.

FIG. 6D is a side view of an embodiment of a septum activator disposedin an inner lumen of a catheter adapter in accordance with the presentinvention, demonstrating fluid flow through the catheter adapter.

FIG. 7 is a cross-sectioned view of an assembled catheter assembly inaccordance with the present invention, prior to activation.

FIG. 8 is a cross-sectioned view of an assembled catheter assembly inaccordance with the present invention, following activation.

FIG. 9 is a cross-sectioned view of an assembled over-the-needlecatheter assembly in accordance with the present invention, prior toactivation.

FIG. 10 is a cross-sectioned view of an assembled over-the-needlecatheter assembly in accordance with a representative embodiment of thepresent invention, following removal of the introducer needle.

FIGS. 11A through 11D are cross-sectioned views of septum having variousfeatures and configuration in accordance with representative embodimentsof the present invention.

FIG. 12 is a cross-sectioned view of an assembled over-the-needlecatheter assembly in accordance with a representative embodiment of thepresent invention, following activation.

FIG. 13 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism and a septum activator in accordance with arepresentative embodiment of the present invention, prior to activation.

FIG. 14 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism and a septum activator in accordance with arepresentative embodiment of the present invention, followingactivation.

FIG. 15 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism and septum activator in accordance with arepresentative embodiment of the present invention, prior to activation.

FIG. 16 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism according to the representative embodiment shownin FIG. 15, following activation.

FIG. 17 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism and septum activator in accordance with arepresentative embodiment of the present invention, prior to activation.

FIG. 18 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism according to the representative embodiment shownin FIG. 17, following activation.

FIG. 19 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism and septum activator in accordance with arepresentative embodiment of the present invention, prior to activation.

FIG. 20 is a cross-sectioned view of a catheter body having a flowcontrol valve mechanism according to the representative embodiment shownin FIG. 19, following activation.

DETAILED DESCRIPTION OF THE INVENTION

The presently preferred embodiment of the present invention will be bestunderstood by reference to the drawings, wherein like reference numbersindicate identical or functionally similar elements. It will be readilyunderstood that the components of the present invention, as generallydescribed and illustrated in the figures herein, could be arranged anddesigned in a wide variety of different configurations. Thus, thefollowing more detailed description, as represented in the figures, isnot intended to limit the scope of the invention as claimed, but ismerely representative of presently preferred embodiments of theinvention.

The term “proximal” is used to denote a portion of a device which,during normal use, is nearest the user and furthest from the patient.The term “distal” is used to denote a portion of a device which, duringnormal use, is farthest away from the user wielding the device andclosest to the patient. The term “activation” of valve mechanism orseptum is used to denote the action of opening or closing of such valve.

An example of a prior art extravascular system is disclosed in U.S. Pat.No. 7,008,404 and shown in FIGS. 1 to 3. An indwelling catheter has, asshown in FIG. 1, a hollow catheter body 1, a catheter 2 fitted into aholder 1 b provided at a distal end of the catheter body 1, a septum 3fitted inside the catheter body 1, and a hollow pusher 4 slidably fittedinside the catheter body 1. The catheter tube 2, septum 3, and thepusher 4 are coaxially aligned in this order.

The catheter body 1 has a tubular shape. An inner surface 1 a is taperedtoward the distal end, with a gradually reduced diameter. The catheterbody 1 is preferably of a transparent or semi-transparent material so asto show the interior, enabling checking of movement inside. Suitablematerials for catheter body 1 include, but are not limited to,thermoplastic polymeric resins such as polycarbonate, polystyrene,polypropylene and the like.

The catheter 2 is press-fitted into the tube holder 1 b whichcommunicates at its proximal end with the inside of the catheter body 1.It is preferred that a lubricating coating is provided to the entiretyor part of the catheter 2 so as to reduce resistance caused by insertionthrough skin or into a blood vessel. Suitable materials for catheter 2include, but are not limited to, thermoplastic resins such asfluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE),polyurethane and the like. Preferably, catheter 2 is formed from athermoplastic hydrophilic polyurethane that softens with exposure tophysiological conditions present in the patient's body.

The septum 3 is of a generally tubular shape having a proximal end 8 anda membrane section 9 having a planar flat surface 10 located at thedistal end 11. Typically, septum 3 further includes a single needle slit3 a or valve aperture located about the centre of membrane section 9,extending through membrane section 9, to facilitate penetration ofseptum 3 by introducer needle 5. The opposing slit surfaces of theneedle slit 3 a are designed to closely conform to the shape ofintroducer needle 5 during storage and prevent an outflow of fluidduring and following removal of the introducer needle 5, then to sealupon removal of the introducer needle 5. With the pusher 4 insertedtherethrough, slit 3 a expands forward in the distal direction andopens, providing fluid communication between the catheter 2 and the rearof the catheter body 1. An annular protrusion 3 b is provided on theinner surface of a rear opening of the septum 3, to engage shoulder 4 cat the distal end of the pusher 4 so as to limit the movement of pusher4 in the proximal direction and prevent the dislocation of the pusher 4from septum 3. A plurality of gaps 3 c are defined between an outerperiphery of the septum 3 and the inner surface 1 a of the catheter body1. Distal and proximal spaces divided by the septum 3 communicate witheach other through the gaps 3 c. Thus the septum 3 slides smoothly withair passing through the gaps 3 c.

The pusher 4 is typically made from a rigid thermoplastic material or alike material, and has a lumen extending therethrough. The pusher 4 hasa tubular portion 4 a, a conical flange 4 b connected to the rearproximal end of the tubular portion 4 a, and a shoulder 4 c protrudingfrom an outer periphery of the tubular portion 4 a. Thus an annularshaped interstitial space is created between tubular portion 4 a and theinner surface 1 a of the catheter body 1. The distal front end of thetubular portion 4 a is chamfered to facilitate its penetration into slit3 a of the septum 3, and is slidably supported by the annular protrusion3 b of the septum 3. The conical flange 4 b has a conical inner surfaceso as to facilitate insertion of the needle 5 thereinto. The peripheralsurface of the flange 4 b contacts the inner surface 1 a of the catheterbody 1 and serves to provide stability to the pusher 4 and maintain thecoaxial position with respect to the catheter 2. However the peripheralsurface of the flange 4 b does not form a fluid seal with inner surface1 a.

The indwelling catheter is prepared for use in such a state as shown inFIG. 1 with the front end of the needle 5 protruding from the front endof the catheter 2. In this state, the needle 5 penetrates through theseptum 3, providing water-tight connection therebetween, and therebypreventing leakage of blood.

The indwelling catheter in this state is inserted into the body of apatient. Then, as shown in FIG. 2, the needle 5 is removed with the tube2 retained in the body of the patient. Septum 3 maintains a fluid sealupon removal of needle 5, being retained catheter body 1 by an annularprotrusion 1 e. Pusher 4 is retained in a proximal position buy theinteraction of annular protrusion 3 b and shoulder 4 c.

A connector 6 (e.g. a luer connector) of a vascular access device isthen inserted from the proximal end of the catheter body 1. When pressedinto the catheter body 1, the connector 6 pushes at its distal end thepusher 4. The pusher 4 thus slides forward in distal direction to pressat its distal end slit 3 a of the septum 3 open thereby activating theflow control valve to the open position. The septum 3 is then pressedagainst the inner surface of a tapered cavity 1 c of the catheter body 1which stops the forward movement of pusher 4 at a distal position asshown in FIG. 3, thus providing communication between the catheter 2 andthe vascular access device. The tapered inner surface 1 a of thecatheter body 1 allows for smooth insertion of the connector 6 and tightcontact between an outer surface 6 a of the connector 6 and the innersurface 1 a through press fitting in order to prevent fluid leaking outof the proximal end of catheter body 1.

However, it should be noted that this valve mechanism has smallinterstitial spaces/areas within the catheter body 1 into which fluidscan flow during use, which give rise to areas of low or no fluid flow.For example, in use, fluid can flow between the peripheral surface ofthe flange 4 b and the inner surface 1 a of catheter body 1 and into theinterstitial space 98 between the outer periphery of tubular portion 4 aand the inner surface 1 a. In addition, fluid can flow into interstitialspace 99 which is gap 3 c between the outer periphery of septum 3 andthe inner surface 1 a of the catheter body 1. The low or no fluid flowthat exists in spaces/areas 98 and 99 makes it very difficult tosubsequently flush out any blood, medicament or air bubbles which mayflow into these areas during use of the catheter.

Referring now to FIG. 4, a catheter assembly 101 is illustrated. Thecatheter assembly 101 generally includes a catheter 12 coupled to adistal end 32 of a catheter adapter 14. The catheter 12 and the catheteradapter 14 are integrally coupled such that an internal lumen 16 of thecatheter adapter 14 is in fluid communication with a lumen 18 of thecatheter 12. The catheter 12 generally comprises a biocompatiblematerial having sufficient rigidity to withstand pressures associatedwith insertion of the catheter into a patient. In some embodiments, thecatheter 12 comprises a metallic material, such as titanium, stainlesssteel, nickel, molybdenum, surgical steel, and alloys thereof. In otherembodiments, the catheter 12 comprises a rigid, polymer material, suchas vinyl. A tip portion 20 of the catheter is generally configured toinclude a beveled cutting surface 48. The beveled cutting surface 48 isutilized to provide an opening in a patient to permit insertion of thecatheter 12 into the vascular system of the patient.

The features of the catheter assembly may be incorporated for use withan over-the-needle catheter assembly. For example, a flexible orsemi-flexible polymer catheter may be used in combination with a rigidintroducer needle to enable insertion of the catheter into a patient.Surgically implanted catheters may also be used.

Once inserted into a patient, the catheter 12 and catheter adapter 14provide a fluid conduit to facilitate delivery of a fluid to and/orretrieval of a fluid from a patient, as required by a desired infusionprocedure. Thus, in some embodiments the material of the catheter 12 andthe catheter adapter 14 are selected to be compatible with bio-fluidsand medicaments commonly used in infusion procedures. Additionally, insome embodiments a portion of the catheter 12 and/or catheter adapter 14is configured for use in conjunction with a section of intravenoustubing 40 to further facilitate delivery of a fluid to or removal of afluid from a patient.

In some embodiments, a proximal end 22 of the catheter adapter 14includes a flange 28. The flange 28 provides a positive surface whichmay be configured to enable coupling of an intravenous tubing or patientconduit 40 to the catheter assembly 101. In some embodiments, the flange28 includes a set of threads 30. The threads 30 are generally providedand configured to compatibly receive a complementary set of threads 44comprising a portion of a male luer or conduit coupler 42. The conduitcoupler 42 is generally coupled to an end portion of the patient conduit40 in a fluid-tight manner. In some embodiments, an inner portion of theconduit coupler 42 is extended outwardly to provide a probe surface 46.

The probe surface 46 is generally configured to compatibly insert withina proximal end 22 of the catheter adapter 14. Following insertion of theprobe 46 into the proximal end 22 of the catheter adapter 14, theconduit coupler 42 is rotated to interlock the coupler 42 and the flange28 (via the sets of threads 30 and 44). During the process ofinterlocking the coupler 42 and the flange 28, the probe 46 is advancedinto the lumen 16 of the catheter adapter 14 to an inserted position (asshown in FIG. 8). The inserted position of the probe surface 46activates the catheter assembly 101 to enable flow of fluid through thecatheter 12 and catheter adapter 14. Once the conduit coupler 42 and thecatheter adapter 14 are attached, a fluid may be delivered to a patientvia the patient conduit 40 and the inserted catheter 12.

Referring now to FIG. 5A, an exploded, cross-sectional view of acatheter assembly 101 is shown. In some embodiments, the catheteradapter 14 includes various design features and components to controland/or limit flow of fluid through the catheter assembly 101. Forexample, in some embodiments of the present invention a septum 50 ispositioned within the inner lumen 16 of the catheter adapter 14. Theseptum 50 generally comprises a flexible, or semi-flexible polymer plughaving an outer diameter that is configured to compatibly seat within agroove or channel 60 formed on an inner surface 24 of the catheteradapter 14. In some embodiments, the septum 50 is barrel shaped having abarrier surface 52 comprising a distal end of the septum 50 and furtherhaving an opening 54 comprising a proximal end of the septum 50. Whenpositioned within the channel 60, the barrier surface 52 of the septum50 divides the inner lumen 16 of the catheter adapter 14 into a forwardfluid chamber 62 and a rearward fluid chamber 64. Thus, the presence ofthe septum 50 controls or limits passage of fluid between the forwardand rearward fluid chambers 62 and 64. Specifically, a chosenconfiguration of the barrier surface 52 of the septum 50 largelydetermines the ability of a fluid to flow through the inner lumen 16 ofthe catheter adapter 14.

For example, in some embodiments the barrier surface 52 of the septum 50is configured to include a slit 56. The slit 56 is configured to provideselective access or flow of a fluid through the barrier surface 52. Insome embodiments, slit 56 is configured to remain in a closed,fluid-tight position until activated or opened by advancing a septumactivator 80 through the slit 56 in a distal direction 390. In someembodiments, the barrier surface 52 comprises one slit 56. In otherembodiments, the barrier surface 52 is modified to include multipleslits 56 and 66, as shown in FIG. 8. For example, the septum 50 caninclude a tri-slit configuration, wherein three slits meeting at acenter point, to form a single opening. In some embodiments, the septum50 comprises a silicone rubber material. In some embodiments, the septum50 consists essentially of a silicone rubber material.

In some aspects, a Parylene coating is disposed on the surface of theseptum 50, include within the surfaces of the slit 56 of the septum 50.Parylene is a chemically resistant coating with good barrier propertiesfor inorganic and organic fluids, strong acids, caustic solutions, gasesand water vapors. In some embodiments, a Parylene coating is applied tothe outer surface of the septum 50 via vapor deposition. A Parylenecoating is a harder material than the substrate material of the septum,such as silicon rubber or a like material. When the septum 50 is coatedwith the typical industry Parylene thickness, which is greater than 1micrometer, the edges of the slit 50 become very stiff. The typicalcoating thickness for Parylene in the industry is in the range of 0.001to over 0.025 millimeters. The harder edge of the slit leaf could indentthe soft face of the slit thus prevent the slit from closing properlyafter the withdrawal of the needle. This increased resistance to closemakes the seal not as effective. Additionally, when the septum 50 iscoated with an industry-standard, thick layer of Parylene, the frictioncoefficient between the septum 50 and the inner surface 24 of thecatheter adapter 14 is reduced, thus reduce the force required to removethe septum 50 from within the catheter adapter 14. On the other hand,when the septum is not coated with Parylene, the silicone septum istacky and difficult to feed in the automated process.

Accordingly, in some configurations, the thickness of the coating can bebetween 0.00005 to 0.0005 millimeters. In other embodiments, thethickness of the coating is between 0.0001 to 0.0035 millimeters. Inother embodiments, the thickness of the coating is between 0.0001 to0.0002 millimeters. With this type of thin layer of Parylene coating,the slit 56 will close easily after the needle withdraws. In addition,the reduced thickness of Parylene coating will provide additionalfriction force between the outer surface of the septum 50 and the innersurface 24 of the catheter adapter 14, increasing the retention force ofthe septum 50.

For some infusion therapy techniques, it may be desirable to permit acontrolled flow of fluid through the septum 50 prior to activating theseptum 50 with the septum activator 80. Thus, in some embodiments theslit 56 further comprises a leak orifice 58. The leak orifice 58 ispositioned in the barrier surface 52 and comprises an opening diametercalculated to permit controlled flow of liquid or air between theforward and rearward chambers 62 and 64. In some embodiments, thebarrier surface 52 is modified to include a single leak orifice 58. Inother embodiments, the barrier surface 52 is configured to includemultiple leak orifices. Still, in other embodiments the barrier surface52 does not include a slit 56, but rather includes at least one leakorifice 58. For these embodiments, the septum 50 generally comprises anelastic material such that when the septum activator 80 is advanced in adistal direction 390, a leading edge 92 of the septum activator 80contacts the barrier surface 52 and stretches the leak orifice 58 toprovide a larger orifice thereby permitting increased flow of air and/orfluid through the catheter adapter 14.

The groove or channel 60 into which the septum is seated comprises arecessed portion of the inner surface 24 of the catheter adapter 14. Theouter diameter of the septum 50 is generally configured to compatiblyand securely seat within the channel 60. For example, in someembodiments the outer diameter of the septum 50 is selected to be bothslightly smaller than the diameter of the channel 60 and slightly largerthan the diameter of the inner lumen 16. As such, the septum 50 isretained within the channel 60 during use of the catheter assembly 101.

For some infusion therapy techniques, air flow between the forward andrearward chambers 62 and 64 may be desirable. For example, for thoseembodiments comprising a septum 50 having a fluid-tight slit 56, passageof air from the forward chamber 62 to the rearward chamber 64 isprohibited prior to opening or activating the septum 50 via the septumactivator 80, as previously discussed. Thus, when the catheter 12 of thecatheter assembly 101 is inserted into the vascular system of a patient,a positive pressure develops within the forward chamber 62 therebypreventing a desired flashback of the patient's blood into the catheteradapter 14. An observable flashback is generally desirable to confirmaccurate placement of the catheter tip 20 within the vein of thepatient. Thus, some embodiments of the present invention includefeatures or elements to enable airflow between the forward chamber 62and the rearward chamber 64, without requiring activation of the septum50 with the septum activator 80. As such, some embodiments of thepresent invention provide an observable flashback, as generally desiredfor infusion procedures.

For example, in some embodiments the barrier surface 52 of the septum 50is modified to include leak orifice 58, as previously discussed. Inother embodiments, a plurality of air vent channels 70 is interposedbetween the septum 50 and the inner surface 24 of the catheter adapter14. The air vent channels 70 relieve the positive pressure within theforward chamber 62 by providing an access for air to bypass the septum50 into the rearward chamber 64. In some embodiments, the air ventchannels 70 are constructed by removing portions of the channel 60surface, resulting in a plurality of generally parallel grooves.

In addition to permitting air flow between the forward and rearwardchambers 62 and 64, the vent channels 70 may be configured to permitfluid to flow through the catheter adapter 14 prior to activating oropening the slit 56 with the septum activator 80. In some embodiments,the rate at which air and/or fluid flows between the forward andrearward chambers 62 and 64 is adjusted by manufacturing the catheteradapter 14 to include a greater or lesser number of vent channels 70. Inother embodiments, the rate at which air and/or fluid flows between theforward and rearward chambers 62 and 64 is adjusted by manufacturing thecatheter adapter 14 to include vent channels 70 having a greater orlesser cross-sectioned area. Thus, in some embodiments the rate at whichair and/or fluid flows between the forward and rearward chambers 62 and64 is increased by manufacturing a catheter adapter 14 having either anincreased number of vent channels 70, or vent channels 70 having agreater cross-sectioned area. Conversely, in other embodiments the rateat which air and/or fluid flows between the forward and rearwardchambers 62 and 64 is decreased by manufacturing a catheter adapter 14having either a decreased number of vent channels 70, or vent channels70 having a lesser cross-sectioned area.

With continued reference to FIG. 5A, the septum activator 80 comprises aprobe-like structure that is primarily housed in the rearward chamber 64of the catheter adapter 14. The septum activator 80 generally comprisesa tubular body 82 having a distal end 84 and a proximal end 86. Thetubular body 82 comprises a rigid or semi-rigid material, such as aplastic or metallic material. The tubular body 82 further comprises aninner lumen 88 for facilitating flow of a fluid and/or liquid throughthe septum activator 80.

The distal end 84 of the tubular body 82 is configured to compatiblyinsert within the opening 54 of the septum 50. The distal end 84 furtherincludes a probing surface 90 which extends through the opening 54 ofthe septum 50 to a position proximal to the barrier surface 52 of theseptum 50, as shown in FIG. 8. The probing surface 90 is advancedthrough the slit 56 and 66, or through the leak orifice 58 as the septumactivator is advanced through the catheter adapter 14 in a distaldirection 390. Advancement of the septum activator 80 through thecatheter adapter 14 will be discussed in detail below, in connectionwith FIGS. 7 and 8.

Still, in other embodiments the septum 50 is coated with a hydrophobiccoating, or a polymeric swelling coating to repel or prevent fluid fromflowing through the vent channels 70. A hydrophobic coating is generallyselected to reduce the surface energy of the septum 50 and/or adapter 14to inhibit blood wicking into the air vents 70. In some embodiments, asurface of the septum 50 or catheter adapter 14 is coated with apolyxylylene polymer material, such as Parylene. In other embodiments, apolyxylylene polymer coating is applied to a vent channel 70 via vapordeposition.

In some embodiments, a dehydrated polymer material is applied to asurface of the septum 50 or catheter adapter 14 which comprises the ventchannels 70. A dehydrated polymer is generally selected to expand orswell upon contact with fluid. As such, when the dehydrated polymerswells, a flow through the vent channels 70 is blocked or occluded bythe swollen polymer. Initially, the dehydrated polymer generallycomprises a thin profile prior to exposure to moisture. However, whenexposed to moisture the polymer absorbs the moisture which increases theprofile of the polymer to block flow through the vent 70. Therefore, bycoating the septum 50 and/or catheter adapter 14 with a desired coating,flow of air is permitted between the forward and rearward chambers 62and 64, yet fluid flow through the vent channels 70 is prevented.

Referring now to FIG. 5B, an embodiment of a septum 150 is shown. Insome embodiments, an outer surface 166 of the septum 150 is modified toinclude a plurality of recessed grooves 72. The recessed grooves 72provide pathways between the forward and rearward chambers 62 and 64through which air and/or fluid may flow. Thus, in some embodiments thechannel 60 does not include air vent channels 70, but rather the outersurface 166 of the septum 150 is modified to provide desired flowbetween the forward and rearward chambers 62 and 64.

The blood pressure of the patient is largely responsible for the rate atwhich blood and air flows through the septum 50 and 150 of the catheterassembly 101. As such, the flow rate through the system is affected bythe combined effective hydraulic diameter of all flow paths. Thus, insome embodiments the hydraulic diameter of the vent channels 70 and/orrecessed grooves 72 are modified to increase or decrease the rate offlow through the catheter assembly 101. In other embodiments, thehydraulic diameter of the vent channels 70 and/or recessed grooves 72are decreased thereby resulting in substantially reduced or stopped flowthrough the ventilation means. The governing equation for controllingthe flow rate through the ventilation means is given in Equation 1,where BP is the blood pressure, A is the surface area of the ventilationmeans, ó is the surface tension of the blood, and P is the perimeter ofthe ventilation means.BP(A)=ó(P)  Equation 1:

Thus, according to Equation 1, when the perimeter of the ventilationmeans is small, the ventilation means will allow air venting, but willprevent blood flow due to the relatively high surface tension (ó) ofblood. However, when the perimeter of the ventilation means isincreased, the surface tension between the blood and the vent isdecreased thereby enabling the blood to slowly leak through the ventsand around the septum to provide desirable, yet controlled flashback.Therefore, by adjusting the various variable of Equation 1, a desiredflow will be achieved. Thus, based on the size and/or number of ventsaround the septum, the catheter assembly design will provide customized,controlled and predictable blood flow around the septum 50 or 150. Insome embodiments, it is desirable to permit slow, controlled blood flowas a means for providing a visual indicator that the catheter is in theblood vessel, without the risk of immediate exposure to the blood. Inother embodiments, it is desirable to only permit air to pass throughthe vents.

Referring now to FIG. 6A, a cross-section view of an interior lumen of acatheter adapter 14 is shown. In some embodiments, catheter adapter 14includes a forward fluid chamber 62 and a rearward fluid chamber 64fluidly connected via a narrowed channel or port 160. As configured andin some embodiments, a fluid pathway 170 is defined whereby a fluid 146flows downstream from the rearward fluid chamber 64, through the port160 and into the forward fluid chamber 62. The fluid pathway 170continues through the forward fluid chamber 62 and exits the distal end32 into a catheter (not shown) or other downstream conduit. While fluid146 fills the entire lumen of the catheter adapter 14, the fluid pathway170 is generally restricted to a narrow pathway through a centralportion of the cross-section of the catheter adapter 14. Accordingly,fluid 146 that is not part of the narrow fluid pathway 170 stagnates orcirculates within dead zones 156. Fluid 146 trapped within these deadzones is prevented from sufficiently mixing with fluid 146 in the fluidpathway 170. In some embodiments, stagnation results in increased,localized concentrations of chemicals, bodily fluids and/or medicamentsthat may lead to precipitation, coagulation or administration ofdangerously high doses of medications. Therefore, in some embodiments ofthe present invention, a septum activator 80 is provided having featuresto eliminate dead zones 156 within the catheter adapter 14 lumen.

Referring now to FIG. 6B, a perspective view of the septum activator 80is shown. In some embodiments, the distal end 84 of the tubular body 82comprises a first diameter 100 that is less than a second diameter 102of the proximal end 86. The narrower distal end 84 is configured tocompatibly insert within the opening 54 of the septum 50, while thewider proximal end 86 is configured to compatibly seat within therearward chamber 64 of the catheter adapter 14. In some embodiments, theseptum activator further includes a tapered middle section 104 to couplethe distal 84 and proximal 86 ends.

In some embodiments, the proximal end 86 of the septum activator 80further includes a retention spring 110. The retention spring 110generally comprises an outwardly biased portion of the tubular body 82configured to compatibly engage a septum activator retention groove 68,as shown in FIGS. 5A, and 7-8. The interaction between the retentionspring 110 and the groove 68 limits the lateral movement of the septumactivator 80 within the lumen 16 of the catheter adapter 14. Thus, thewidth of the retention groove 68 determines or limits the distance oftravel for the septum activator 80 within the catheter adapter 14.Additionally, the interaction between retention spring 110 and thegroove 68 prevents removal of the septum activator 80 from the catheteradapter 14. In some embodiments, the septum activator 80 comprises aplurality of retention springs 110, while in other embodiments theseptum activator 80 comprises a single retention spring 110.

In some embodiments, the septum activator 80 further comprises featuresfor directing or diverting fluid flow around and/or through the septumactivator 80. Flow diversion may be important to prevent stagnation orcoagulation of fluids within dead zones 156 of the septum activator 80and/or the lumen 16 of the catheter adapter 14 resulting in blockages.Additionally, stagnation of fluid flow through the catheter assembly 101may result in a build up of undesirable concentrations of medicamentswithin the catheter adapter 14 and/or the septum activator 80, aspreviously discussed. Undesirable high concentrations may result inineffective treatment causing serious side effects, including death.Thus, in some embodiments the septum activator 80 is modified to includeflow deflectors 120 and flow diversion channels 130 to provide aflushable catheter assembly 101 system.

The flow deflectors 120 generally comprise inwardly and outwardly angledportions of the septum activator 80 outer surface. The flow deflectors120 are positioned so as to be protrude into a flow path through thecatheter adapter 14. Thus, as the fluid contacts the flow deflectors 120the path of the fluid flow is disturbed. This disturbance results inredirecting the fluid flow both through the inner lumen 88 of the septumactivator 80, and between the outer surface of the septum activator 80and the inner surface 24 of the catheter adapter 14. In some embodiment,the retention spring 110 also serves as a flow deflector 120.

A flow diversion channel 130 is provided to permit exchange of fluidbetween the lumen of the catheter adapter 16 and the inner lumen 88 ofthe septum activator 80. Thus, the flow diversion channel 130 preventsstagnation and/or clotting of fluid between the inner surface 24 of thecatheter adapter 14 and the outer surface of the septum activator 80. Insome embodiments, the flow diversion channel 130 comprises a window oropening in the surface of the tubular body 82. In other embodiments, theflow diversion channel 130 further comprises a flap or angled surface tofurther direct fluid to flow through the channel 130.

The proximal end 86 of the septum activator 80 further includes acontact surface 140. The contact surface 140 comprises the most proximalend portion of the septum activator 80 and is positioned within therearward chamber 64 of the catheter adapter 14 adjacent to the proximalopening 26 of the catheter adapter 14, as shown in FIG. 7, below.

Referring now to FIG. 6C, an embodiment of a septum activator 180 isshown as positioned in the lumen of a catheter adapter 14 (shown inphantom). In some embodiments, septum activator 180 is configured toinclude various re-circulation features. For example, in someembodiments septum activator 180 includes various vents 200 configuredto divert fluid from the fluid pathway 170 into the dead zones 156.Thus, as fluid flows into and through the septum activator 180, thefluid within the septum activator 180 passes through the vents 200 andinto the dead zones 156 between the outer surface of the activator 180and the inner wall surface of the catheter adapter 14. The divertedfluid intermixes with the fluid in the dead zones 156 to flush fluidfrom the dead zones 156 and thus prevent stagnation and/oroverconcentration, as previously discussed.

In some embodiments, septum activator 180 is further modified to includeflushing fins 220. Flushing fins 220 generally comprise perpendicularextension of the outer surface of the activator 180 that extend into thedead zones 156 between the activator 180 and the inner wall surface ofthe catheter adapter 14. The flushing fins 220 are provided to divertand redirect fluid within the fluid pathway 170 into the dead zones 156.As such, fluid within the dead zones 156 is intermixed with fluid in thefluid pathway 170 to prevent stagnation and/or overconcentration offluid within the catheter adapter 14.

Finally, in some embodiments the flow diversion channel 130 is modifiedto include a flow deflector 230. The flow deflector 230 comprises abeveled, distal surface of the flow diversion channel 130 positioned todivert fluid within the fluid pathway 170 into the dead zones 156 of theforward fluid chamber 62. Thus, as fluid 146 flows through the septumactivator 180, a portion of the fluid is diverted through the flowdiversion channel 130 and into the dead zone 156 via the flow deflector230, as shown in FIG. 6D.

With continued reference to FIG. 6D, a cross-sectioned septum activator180 positioned within a cross-sectioned catheter adapter 14. Aspreviously discussed, recirculation features may be added to both theproximal 86 and distal 186 ends of the septum activator 180. In someembodiments, the proximal end 86 of the septum activator 180 is modifiedto include curved window features 240 that redirect the flow of a fluid246 into the dead zones 156 of the rearward fluid chamber 64. Thus, thecurved surface 242 of the window feature 240 alone and/or in combinationwith the other recirculation features promotes intermixing of the fluidwithin the dead zones 156 to prevent stagnation and overconcentration offluids within the catheter adapter 14.

In some embodiments, the recirculation features are positioned in asymmetrical configuration to induce best flushing. In other embodiments,the recirculation features are positioned in an asymmetricalconfiguration to induce best flushing. Finally, in some embodiments therecirculation features are used in combination with additionaldiffusing, circulating and recirculating features of the septumactivator 180 to aid the fluid flushing capability of the septumactivator 180. In light of the foregoing disclosure, additional surfacesof the septum activator 180 may be modified to increase or decrease flowefficiency, mixing and flushing of fluids within the septum activator180, as desired.

Referring now to FIG. 7, a cross-sectional view of the assembledcatheter assembly 101 is shown prior to activation of the septum 50 viathe septum activator 80. Prior to activation, the septum activator 80 isentirely positioned within the rearward fluid chamber 64 of the catheteradapter 14. Additionally, the retention springs 110 are engaged withinthe retention groove 68 and positioned near the proximal end of theretention groove 68. The contact surface 140 of the septum activator 80is positioned near the opening 26 of the catheter adapter 14, such thata proximal opening 142 of the septum activator 80 is in a planegenerally parallel to the plane of the catheter adapter opening 26.Finally, the outwardly biased retention springs 110 bind on the surfaceof the groove 68 thereby maintaining the inactivated position of theseptum activator 80 within the catheter adapter 14.

Referring now to FIG. 8, a cross-sectional view of the catheter assembly101 is shown following activation of the septum 50 via the septumactivator 80. Upon insertion of the coupler 42 into the proximal opening26 of the catheter adapter 14, the probe portion 46 of the coupler 42contacts the contact surface 140 of the septum activator 80. The septumactivator 80 is advanced in a distal direction 390 as the coupler 42 isfurther inserted into the proximal opening 26 of the catheter adapter14. As the coupler 42 is advanced further into the proximal opening 26,the probing surface 90 of the septum activator 80 passes through thebarrier surface 52 of septum 50. As such, the probing surface 90 of theseptum activator 80 is positioned within the forward chamber 62providing a fluid pathway through the septum 50.

In some embodiments, the catheter assembly 101 is configured to permitthe septum activator 80 to return to a position entirely within therearward chamber 64 following removal of the coupler 42 from thecatheter adapter 14. Thus, when the coupler 46 is removed or detachedfrom the catheter assembly 101, the fluid pathway through the septum 50is reclosed. In some embodiments, the retention spring 110 is configuredto flex inwardly upon contact between the contact surface 140 of theseptum activator 80 and the probe 46 of the coupler 42. When theretention spring 110 flexes inwardly, the probing surface 90 of theseptum activator 80 is temporarily advanced in a distal direction 390 tobias open the slits 66 and 56, or the leak orifice 58. When contactbetween the probe 46 and the contact surface 140 ceases, the retentionspring 110 returns to its relaxed position. The relaxed positionwithdrawals the probing surface 90 of the septum activator 80 from thebarrier surface 52 thereby permitting closure of the slits 66 and 56.

Referring now to FIG. 9, a cross-sectional view of a catheter assembly300 is shown incorporating an introducer needle 350. The proximal end352 of the needle 350 may be coupled to a needle hub (not shown) or aninsertion assembly (not shown) to facilitate a user in holding andmanipulating the needle 350 during catheterization. For purposes ofclarity in the present illustration the remainder of the needle assemblyhas been removed.

Prior to activation, septum activator 380 is entirely positioned withinthe rearward chamber 364 of catheter adapter 314. A pathway is providedthrough the inner lumen 316 of the activator 380 so as to allow passageof introducer needle 350. A middle portion of the needle 350 passesthrough septum 356 and continues through the forward chamber 362 andinto the flexible catheter 312. A tip portion (not shown) of the needle350 extends beyond a tip portion (not shown) of the catheter 312 suchthat the needle tip is available to gain access to the vasculature of apatient.

The slit 366 of septum 356 is biased open by introducer needle 350. Insome embodiments, a seal is formed between the outer surface of theneedle 350 and the slit 366. Thus, fluid and air flow are prevented frombypassing the septum by way of the interface between the needle 350 andthe slit 366. In some embodiments, a channel or pathway is providedbetween the slit 366 and the needle 350 to permit controlled leakage orflow between these two components.

In other embodiments, a lubricant such as a non-wetting lubricant isapplied to the interface between the needle 350 and the slit 366 tofurther eliminate possible leakage of fluid and/or air. A non-wettinglubricant may also be beneficial to prevent tearing or other damage tothe slit that may occur when the needle is removed from the catheterassembly following catheterization. A non-wetting lubricant may alsofacilitate proper realignment of the slit 366 halves following removalof the needle 350. Non-limiting examples of a non-wetting lubricantinclude known Teflon based non-wetting materials such as Endura, fromEndura Coating Co.; A20, E-20, 1000-S20, FEP Green, PTFE and X-40 fromTiodize; Cammie 2000 from AE Yale; 21845 from Ladd Research; MS 122-22,MS 122DF, MS-143DF, MS-122V MS-122VM, MS143V, MS-136W, MS-145W, U0316A2,U0316B2, MS-123, MS-125, MS-322 and MS-324 from Miller-Stepheson; and633T2 from Otto Bock can also be used. Various non-Teflon basednon-wetting lubricant type materials include Dylyn, from ART; Nyebar,Diamonex, NiLAD, TIDLN, Kiss-Cote, Titanium oxide; FluocadFluorochemical Coating FC-722, from 3M; Permacote from Dupont; PlasmaTech 1633 from Plasma Tech, Inc.; and silicone sprays.

In some embodiments, distal end 384 of the septum activator 380 iselongated such that contact surface 340 is positioned closer to proximalopening 326 of the catheter adapter 314. Accordingly, a coupler having ashortened probe portion (not shown) may sufficiently contact the contactsurface 340 to advance the distal end 384 through the septum 356. Inother embodiments, the distal end 384 of the septum activator 380 isconfigured to include an inner diameter of substantially the same sizeand the outer diameter of the introducer needle 350. As such the innerdiameter of the distal end 384 is configured to allow passage of theneedle 350 while maintaining minimal tolerance 382 between the outersurface of the needle 350 and the inner surface of the septum activator380 distal end 384. This minimal tolerance 382 provides a seal therebypreventing leakage or flow of blood between the needle 350 and theseptum activator 380 while withdrawing the needle 350 from the catheterassembly 300.

In some embodiments, a translating groove 368 is provided within therearward chamber 364. The translating groove 368 generally comprises anannular recess having a determined length 370. Translating groove 368 isfurther configured to receive flushing fins 320 such that the flushingfins 320 are retained within the groove 368. Thus, length 370 representsthe maximum lateral distance which septum activator 380 is permitted totravel within the rearward chamber 364. In some embodiments, a proximalend of groove 368 is defined by an annular ridge 372. In otherembodiments, a distal end of groove 368 is defined by a second annularridge 374. Still, in other embodiments the second annular ridge 374forms a proximal end of septum channel 60.

Referring now to FIG. 10, a cross-sectional view of catheter assembly300 is shown following removal of introducer needle 350. Upon removal ofintroducer needle 350, slit 366 of septum 356 is no longer biased openand therefore recloses and seals to prevent flow of fluids and/or airvia the slit 366. As previously discussed, in some embodiments slit 366includes a leak orifice (not shown) to permit controlled flow betweenthe forward and rearward chambers 362 and 364. In other embodiments, aplurality of ventilation channels 70 are provided between the outersurface of the septum 356 and the septum channel 60.

Referring now to FIGS. 11A through 11D, septum 356 may include variousconfigurations and features to stabilize distal end 384 of the septumactivator 380. For example, in some embodiments septum 356 is configuredto include an inner diameter 358 sized substantially equal to the outerdiameter of the distal end 384 of septum activator 380, as shown in FIG.11A. In other embodiments, septum 356 is configured to have an interiorannular ridge or protrusion 360 having an inner diameter 358 sizedsubstantially equal to the outer diameter of distal end 384, as shown inFIG. 11B. Thus, in both of these embodiments distal end 384 is radiallysupported by septum 356.

With reference to FIG. 11C, in some embodiments an interior surface 376of septum 356 is modified to include one or more reliefs 391. In someembodiments, relief 391 comprises a concave annular recess configured toreceive a positive feature 392 comprising a portion of distal end 384 ofthe septum activator 380. In other embodiments, relief 391 comprises asingular indent sized and configured to receive feature 392 of theseptum activator 380. Still, in other embodiments relief 391 comprises apositive feature and feature 392 comprises a negative or recessedfeature (not shown). Thus, in some embodiments the interaction betweenrelief 391 and feature 392 provides both radial support and axialretention of the septum activator 380 within the catheter adapter 314.This configuration may eliminate the need for additional retentionfeatures, such as clips and retention grooves.

Referring now to FIG. 11D, septum 356 includes a domed profile 394 tocounteract pressure applied to the distal side 386 of the septum 356following removal of introducer needle 350. The domed profile 394provides additional strength to the distal side 386 of the septum 356thereby increasing the fluid pressure required to defeat the septum 356.In some embodiments, as the blood reaches the septum 356 the domedprofile 394 assists the septum 356 in closing due to the pressure fromthe blood flow within the forward chamber 362. In other embodiments,septum 356 comprises a generally flat profile, as shown in FIGS. 5A, 5Band 7 through 11C or may include a combination of flat and curvedsurfaces (not shown).

Referring now to FIG. 12, a cross-sectional view of catheter assembly300 is shown following activation of septum 356 via septum activator380. Upon insertion of a coupler 342 into the proximal opening 326 ofthe catheter adapter 314, the probe portion 346 of the coupler 342contacts the contact surface 340 of septum activator 380. Septumactivator 380 is accordingly advanced in a distal direction 390 as thecoupler 342 is further inserted into proximal opening 326 therebycausing flushing fins 320 to translate within translating groove 368. Ascoupler 342 is advanced further into the proximal opening 326, probingsurface 348 of the septum activator 380 passes through the slit 366 ofseptum 356. As such, the probing surface 348 of the septum activator 380is positioned within the forward chamber 362 providing a fluid pathwaythrough the septum 356.

Referring now to FIGS. 13 through 20, a number of valves in accordancewith some embodiments are shown which aim to further eliminate or reduceareas of low or no fluid flow occurring within a vascular access devicecontaining a valve mechanism comprising a septum and septum activator orpusher.

FIGS. 13 and 14 show an embodiment of the invention in which a sleeve 45is used to prevent fluid from flowing into any interstitial spaces whichare low or no flow fluid areas.

FIG. 13 shows a septum 43 which forms a fluidic seal in the lumen 341 ofcatheter body 41 after removal of the needle, with septum activator orpusher 344 in the proximal position. Sleeve 45 is attached around pusher344 to form a fluid seal between an outer periphery 53 of proximalportion 348 of pusher 344 and inner surface 354 of lumen 341. Thus, nofluid can flow between the proximal end of pusher 344 and the innersurface 354 of lumen 341 into the interstitial space 498. FIG. 14 showspusher 344 in the distal position in which fluid can only flow via thelumen 51 of pusher 344. Sleeve 45 still maintains a fluidic seal betweenouter periphery 53 of pusher 344 and inner surface 54 of lumen 341.Thus, no fluid can flow into the interstitial spaces 498. In addition,the tapered outer surface 351 of the distal portion of sleeve 45 reducesthe size of the interstitial space 498 when pusher 344 is in the distalposition. Sleeve 45 is made from a softer elastomeric material, such asliquid silicone rubber for example, and is attached to pusher 344through suitable molding procedures, such as insert molding, injectionmolding, and other molding techniques or a combination of moldingtechniques.

FIGS. 15 and 16 show another embodiment of the invention having valvemechanism which uses a seal at the proximal end 65 and distal end 75 ofa tubular septum activator 365, to prevent fluid from flowing intointerstitial spaces 698 and 699 between activator 365 and the innersurface 74 of the lumen 363 of the catheter body 61. Distal seal 75 isincorporated into septum 63 to prevent any fluid flowing between thedistal end of activator 365 and the proximal surface of septum 63 whenpusher is in the proximal position as shown in FIG. 15 or the distalposition as shown in FIG. 16. Proximal seal 65 is a continuous torus ortoroidal-shaped band around the outer circumference of the proximal endof activator 365 which forms a fluid seal with the inner surface 74 ofthe lumen 363 of the catheter body 61 in both the proximal and distalactivator positions. The proximal seal 65 is made from a softerelastomeric material, such as liquid silicone rubber for example and isover-molded onto activator 365 and retained in position by lip 367 onthe outer surface of the proximal end of activator 365. Activator 365has a number of fins 369 extending from and evenly distributed aroundthe circumference of the outer surface 371. These fins 369 aresufficiently long to contact a portion 73 of the inner surface 74 oflumen 363 and are used to limit the movement of activator 365 along thecatheter body by contact with the septum 63 in the distal direction andcontact with indent or step 378 of the inner surface 74 in the proximaldirection.

FIGS. 17 through 20 show some embodiments having valve mechanisms whichare configured to exclude small confined interstitial spaces, therebyeliminating areas of no to low fluid flow.

FIGS. 17 and 18 show an embodiment in which the septum 83 encases themajority of activator 383. Activator 383 includes a head section,tubular section and a plunger. Plunger 381 which has a diameter at leastequal to that of lumen 385 of the catheter body 81 such that no fluidcan pass between the inner surface 94 and plunger 80 is located at theproximal end of activator 383. Septum 83 has an external diameter atleast equal to that of lumen 82 along its entire length such that nointerstitial space is present between septum 83 and inner surface 94 oflumen 385. In addition, septum 83 has a lumen 85, the internal diameterof which is equal to the external diameter of tubular section 87 ofactivator 383 thereby forming an additional fluid seal along the lengthof tubular section 87. Furthermore, the relative lengths of activator383 and septum 83 are such that the distal face 389 of plunger 381 is inintimate contact with the proximal end 388 of septum 83 when activator383 is in the distal position, as shown in FIG. 18. Thus, there is nointerstitial space between plunger 381 and septum 83. The head sectionis located at the distal end of activator 383 and includes longitudinalslots 387 in the side wall of lumen 91 in order to allow fluid flow todiverge out of lumen 91 of activator 383 and reduce the possibility of ano or low flow area 393 around the distal face of septum 83 at the innersurface 74.

FIGS. 19 and 20 show a further embodiment of a valve mechanism in whicha septum 103 includes a tubular section 107 having a distal end 108 anda membrane section 109 having a proximal planar surface located at theproximal end 105. The tubular section 107 of septum 103 is substantiallydisposed within septum housing 111 and is prevented from distal movementby shoulder or annular recess 121 formed in surface of lumen 385. Afluidic seal is formed between the periphery of membrane section 109 andinner surface 114 of the proximal section 110 of lumen 385 to preventfluid leakage past septum 103 when the valve is closed. In someembodiments, septum 103 further includes a needle slit 113 or valveaperture located about the centre of membrane section 109, extendingthrough membrane section 109, to facilitate penetration of septum 103 byintroducer needle 5. A septum activator 304 is located in the proximalsection of lumen 385 and includes a tubular portion 115. In someembodiments, tubular or sleeve portion 115 further includes a pluralityof longitudinal slots or flow channels 116 in the side wall, distributedevenly around the circumference of tubular potion 115 and located at thedistal or actuating end 117 such that a gap is formed between theactuating end 117 and membrane 109.

FIG. 19 shows septum activator 304 in the proximal position followingremoval of introducer needle 5. In particular, the actuating end 117 ofseptum activator 304 is positioned against the proximal planar surfaceof membrane section 109 of septum 103 to form an interface. The diameterof lumen 385 in proximal section 310 is approximately equal to theexternal diameter of connector 106 (e.g. a luer connector) of a vascularaccess device, septum activator 304 and membrane section 109, such thatthere are no interstitial spaces between the connector 106 (shown inFIG. 20), a contact end of septum activator 304 and membrane section109. The inner surface 114 and proximal section 310 of the first lumen385 are further sealed by membrane section 109.

Referring now to FIG. 20, septum activator 304 is shown in the distalposition whereby connector 106 has repositioned septum activator 304forward in a distal direction thereby causing actuating end 117 ofseptum activator 304 to deform membrane section 109. This deformationresults in the formation of a fluid pathway whereby fluid bypassesmembrane section 109 via slots 116, thereafter flowing between peripheryof membrane section 109 and inner surface 114, and guided throughopening 118 in the side wall of tubular portion 107. This divergentfluid path around the periphery of membrane section 109 causes aturbulent fluid flow which reduces the possibility of stagnation or alow flow area occurring near shoulder 119 in lumen 385. Fluid thencontinues to flow along the internal diameter of tubular portion 107 andinto the distal section 112 of lumen 385.

Any septum described herein may be made of a variety of suitablematerials and through a variety of suitable manufacturing methods. Forexample, the septum may be formed from liquid silicone rubber throughsuitable molding procedures, such as insert molding, injection molding,other molding techniques, or a combination of molding techniques. Theseptum 103, or any septum described herein, may also include a coatingof antimicrobial substance on any of its surfaces, especially thosesurfaces which have contact with fluid.

The present invention may be embodied in other specific forms withoutdeparting from its structures, methods, or other essentialcharacteristics as broadly described herein and claimed hereinafter. Thedescribed embodiments are to be considered in all respects only asillustrative, and not restrictive. The scope of the invention is,therefore, indicated by the appended claims, rather than by theforegoing description. All changes that come within the meaning andrange of equivalency of the claims are to be embraced within theirscope.

The invention claimed is:
 1. A system for controlling fluid flow in acatheter assembly, comprising: an intravenous catheter assembly having acatheter adapter and a needle hub, the catheter adapter having an innerlumen; a septum disposed within a portion of the inner lumen; aventilation channel interposed between the septum and an inner surfaceof the inner lumen of the catheter adapter, the ventilation channelhaving a surface area and perimeter selected to permit passage of airand prevent passage of blood; a slit formed through the septum; acoating, formed of vapor deposited polyxylylene polymers, disposedwithin the slit of the septum, the coating having a thickness of betweenapproximately 0.00005 to 0.0005 millimeters; and an introducer needlehaving a first end and a second end, the first end being coupled to theneedle hub and the second end extending through the inner lumen of thecatheter adapter, a middle portion of the introducer needle beingpositioned within a portion of the septum.
 2. The system of claim 1,wherein the thickness of the coating is between 0.0001 to 0.0002millimeters.
 3. The system of claim 2, further comprising a lumenforming a fluid pathway through the septum activator, the lumen havingan inner diameter configured to permit passage of the introducer needle.4. The system of claim 1, further comprising a septum activator disposedwithin a portion of the inner lumen adjacent to the septum, a distal endof the septum activator contacting a proximal surface of the septum, anda proximal end of the septum activator being positioned adjacent to anopening of the catheter adapter, wherein the proximal end of the septumactivator is accessed by inserting an external device into the openingof the catheter adapter.
 5. The system of claim 1, wherein the septumactivator comprises a plurality of vents and flow diverters configuredto improve circulation of a fluid within at least one of the septumactivator and an interstitial space between the septum activator and theinner surface of the inner lumen.
 6. The system of claim 1, furthercomprising a flow vent interposed between an outer surface of theintroducer needle and an inner surface of the septum activator lumen,wherein a rate of flow through the flow vent is determined by adjustingat least one of an outer diameter of the introducer needle and the innerdiameter of the septum activator lumen.
 7. A method manufacturing acatheter assembly having features for controlling fluid flow within thecatheter assembly, the method comprising: providing an intravenouscatheter assembly having a catheter adapter and a needle hub, thecatheter adapter having an inner lumen; disposing a septum within theinner lumen, the septum having a slit therethrough; providing aventilation channel between the septum and an inner surface of the innerlumen of the catheter adapter, the ventilation channel having a surfacearea and perimeter selected to permit passage of air and prevent passageof blood; coating the septum and the slit with a coating having athickness of between approximately 0.00005 to 0.0005 millimeters, thecoating being formed of vapor deposited polyxylylene polymers;positioning an introducer needle within the catheter adapter, wherein afirst end of the introducer needle is coupled to the needle hub and asecond end of the introducer needle extends through the inner lumen ofthe catheter adapter, a middle portion of the introducer needle beingpositioned within a portion of the septum.
 8. The method of claim 7,wherein the thickness of the coating is between 0.0001 to 0.0002millimeters.
 9. The method of claim 8, further comprising providing alumen forming a fluid pathway through the septum activator, the lumenhaving an inner diameter configured to permit passage of the introducerneedle.
 10. The method of claim 7, further comprising disposing a septumactivator within a portion of the inner lumen adjacent to the septum, adistal end of the septum activator contacting a proximal surface of theseptum, and a proximal end of the septum activator being positionedadjacent to an opening of the catheter adapter, wherein the proximal endof the septum activator is accessed by inserting an external device intothe opening of the catheter adapter.
 11. The method of claim 7, furthercomprising modifying the septum activator to include a plurality ofvents and flow diverters configured to improve circulation of a fluidwithin at least one of the septum activator and an interstitial spacebetween the septum activator and the inner surface of the inner lumen.12. The method of claim 8, further comprising providing a flow ventinterposed between an outer surface of the introducer needle and aninner surface of the septum activator lumen, wherein a rate of flowthrough the flow vent is determined by adjusting at least one of anouter diameter of the introducer needle and the diameter of the septumactivator lumen.
 13. An intravenous catheter assembly, comprising: acatheter adapter having an inner lumen, the inner lumen having aproximal end, a distal end and a middle portion; a recess forming themiddle portion of the inner lumen; a septum disposed within the recess,the septum forming a defeatable barrier between the proximal end and thedistal end of the inner lumen; a ventilation channel interposed betweenthe septum and an inner surface of the inner lumen of the catheteradapter, the ventilation channel having a surface area and perimeterselected to permit passage of air and prevent passage of blood; acoating disposed within a slit of the septum, the coating having athickness of between approximately 0.00005 to 0.0005 millimeters, thecoating being formed of vapor deposited polyxylylene polymers; anintroducer needle positioned within the inner lumen, a portion of theneedle extending through the inner lumen, such that a tip portion of theintroducer needle extends beyond the catheter adapter, a portion of theintroducer needle being inserted through the septum; a septum activatorpositioned within the proximal end of the inner lumen, the septumactivator having a pathway through which the introducer needle isinserted, the septum activator further having a first end for biasingopen a slit of the septum, and a second end having a contact surface;and an opening forming a proximal end of the catheter adapter, whereinan external device is inserted through the opening to contact thecontact surface of the septum activator thereby advancing the first endof the septum activator through the slit of the septum and against thecoating.
 14. The assembly of claim 13, wherein the thickness of thecoating is between 0.0001 to 0.0002 millimeters.
 15. The assembly ofclaim 13, further comprising a flow vent interposed between an outersurface of the introducer needle and an inner surface of the septumactivator pathway, wherein a rate of flow through the flow vent isdetermined by adjusting at least one of an outer diameter of theintroducer needle and an inner diameter of the septum activator pathway.16. The assembly of claim 13, wherein the septum activator furthercomprises a plurality of vents and flow diverters configured to improvecirculation of a fluid within at least one of the septum activatorpathway and an interstitial space between the septum activator and theinner surface of the catheter adapter inner lumen.
 17. The assembly ofclaim 13, wherein a proximal surface of the septum further includes acavity for housing a distal end of the septum activator, and wherein adistal surface of the septum is dome-shaped.